The development of platforms for the sensitive and straightforward measurement of protein levels in clinical samples is an important goal that will facilitate expanded use of protein biomarkers in disease diagnosis. In order to provide useful information, detection schemes must exhibit high levels of specificity, low limits of detection, and robust performance in biological fluids like blood and serum. Given the emergence of multi-protein signatures for cancer and other diseases, multiplexing is also a valuable feature. The inclusion of internal and external controls and calibrators—critical for the development of accurate diagnostic assays—also requires multiplexing.
A variety of high-performing protein detection platforms are under development, and many of the most specific and sensitive use micro- and nanomaterials in their sensing schemes. Barcoded nanoparticles, nanowire transistors, enzyme-labeled beads, and microfluidic immunoarrays used with electrochemical readout all show promise for the development of biomarker analyzers. Challenges remain, however, pertaining to the development of simple analysis systems that are cost-effective and robust enough for clinical use.